Dry cell and method of manufacture



Nov. 23 1926. 1,608,196 L.. G. BERIGAN DRY CELL ND METHOD OF MANUFACTURE Filed Feb. 5f 1925 Patented Nor. 23, 1926.

,Uhlil STATS rear LEROY Gt. ESERIGAN; OF MADISON, WISCONSIN,ASSIGNOR TG .FR'NCEQBATTEY CGM- P'NY, OF MADISGN, WSCONSIN, A. COBEORATION F WSCONSN.

DRY CELL AND METCD 0F MANUACTURT.

.application filed February 5, 1925. Serial No. 7,046.

Such a core, or body, is quit-.e ragile.4

Hitherto, it has been the most usual prac- 4tice to wrap the core in cheese cloth and secure the wrapping on the core by means of wrappings of thread. Many eiiforts have been made to evolve practices suitable for -factory operations which omit the cheese cloth wrapping or provide some substitute tor the securing ofthe wrapper on the core by winding a string or thread about the core and tying the string or thread. Many of the methods which have been proposed involvo the use of coatings which are applied either to the surface ot the depolarizing body, or core, or to the wrapping which envelopes the core. There are objections to the use ot such coat-ings, in practice. One series objection is that the use ot the coating tends to inhibit or interfere with the tree electrolytic action which should occur when the cell is in use. f l

During periods when the cost of cheese cloth is not excessive, there are reasons, in`

factory practice, why it is desirable to use such a wrapping, provided the labor eX- pense can be kept low enough and provided the operation ot applyingV the wrapper can be so facilitated as to insure a maximum output ot product.

The present invention utilizes'an exceedingly simple and ctlcctive method ot applyino; a bibulous cover, or wrapping, to a core ot the character mentioned; and the wrapping, when applied in accordance with the improved method, will not interfere with the tree chemical action which is desired in the cell. According to the improved method, the

. wrapper, which preferably comprises a strip cip cheese cloth., has its upper and lower man gins dipped in melted paran, ore in other suitable adhesive. The core is then rolled into the wrapper, leaving the ends ot the wrapper projecting in the forro ot tubular extensions. These tubular extensions then are tucked in in 'folds over the ends ot the core, and adhere' together so as to adequately secure the wrapper on the core.

The invention. is illustrated in its preferred embodiment in the accompanying drawing, in which-.-

Fig. l represents a core embodying the invention, 'from which a portion of the wrapping hasA been opened; Fig. 2, an elevational view ot the completed core; llig. 8, a top plan view of the same; Fig. Il, a bottom plan view'ot the same; and Fig. a. sectional view ot a cell in accordance with the invention.

ln the illustration given., Arepresents a core for a dryv cell molded from a mixture comprising a suitable carbonaceous material. and equipped with a carbon pencil Af; and `B represents a wrapper which preferably is a strip of cheese cloth, but which may be a strip of paper. r)The strip of cheese cloth, or other bibulous wrapper, preferably is ot such length as to wrap upon the core and have the vertical margins overlap slightly. The upper and lower margins are designated l and 2. These margins preferably are dipped in melted paraffin. rlfhe space between the upper and lower margins lis ot a width corresponding approximately with the height ot the bod;7 A. The upper and lower dipped, or coated, margins l and 2 are ot' suitable width to enable them to beI folded over and tucked down on the end surfaces ot the body A.

The preferred method ot applyingP the wrapper, where the operation is performed by hand, is to roll the core in the wrapper until the wrapper completely envelope the cylindrical surface ot the core andthe vertical margins otl the wrapper overlap. thus leavingr the paraiiined margins projecting' in the-torni ot cylindrical extensions. These extensions are then bent over in 'folds and pressed against the end surfaces of the core. Thus, in Fig. gl, the upper margin l hasv been tucked down upon the upper surface ot the body A to torni the tucks, or Jfolds` la; and yin Fig, e. the lower margin has been tucked in and pressed against the loweil surface ofthe body A in the form ot tucks. or folds, 2a. These folds overlap and adhere to each other and adhere also to the end surt'aces ot the core. 'lhe parain may cool, otl

course, before the wrapper is applied to the core, but it is found, 1n practice, that when the parallined marginsare pressed upon each lother and against the end surfaces of the core, the tucks will adhere together and to the core in such a manner as to provide a very secure envelope for the core.

ln Fig. 2, the vertical margins 3 and 4 of the wrapper are shown as overlapping. In practice, the overlap may be very slight, or may even be omitted.

After the core has been formed in the manner described, it is introduced into a zinc can 5, and the cell is provided with an electrolyte (l which sets in the form of a paste. The electrolyte may be introduced either before or after theinsertion of the core. ln the illustration given, the cell is completed by introducing a. pasteboard washer 7 above the core and pouring in melted pitch, or wax, to form a seal 8.'

It has been the practice,` hitherto, where a cheese cloth wrapping has been applied to the core and secured by wrappings of twine, or thread, to then dip the lower end of the wrapped core in parat-lin. Another expedient is to place a paratlined disk in the bottom of the zinc can, for insulation. In accordance with the improved process, the paraffined tucks at the bottom of the core afford a sufficient insulation between the bottom of the core and the bottom of the can.

The Wrappers may be applied to the cores very expeditiously by hand, if desired. However, the improved method lends itself readily to machine yoperation in effecting the wrapping of the core. Any suitable ina-- chine, or apparatus may be employed for effecting the wrapping and tucking operations. Thus, the cost of applying to a core a wrapper which will not interfere with the action of the cell may be reduced to a minimum, and a hitherto tedious method of applying wrappers is elin'iinated. The improved process, obviously, is an important item .in the manufacture of dry cells of this type, where the manufacture in some factories may Vrun into the hundred thousands per day.

A further advantage of the improved method of wrapping ,is that the Wrapper is applied very smoothly to the core, and thus a cell may be'completed without danger of trapping air` in the electrolyte in the annular space between the core and the can. Hence, there is a uniform distribution of electrolyte between the core and the can. As is known in the use of the cell, as well as in the manufacture of the cell, the cheese cloth serves to prevent the migration of particles ofcarbon, or graphite, into the electrolfite, and thus tends to prevent injury to, or destruction of, the cell.

The paratin employed to coat, or saturate, the upper and lower margins of the cheese cloth is an insulating` adhesive which is of rather a waxy nature. This material gives to the wrapper, at the coated por-- tions, a certain degree of stiffness, so that the tucks of the wrapper when pressed against the ends of the core assume a set, or fixed, condition. This adhesive is not readily alfected by the electrolyte in its fluid condition, or before it has become gelatinizcd; hence, the core may be introduced into a cup containing `the fluid electrolyte in sufficient quantity to lill, or approximately fill, the annular' space, and this may be done without danger of disintegrating the adhesive or causing a loosenin of the tucks. Any suitable adhesive whic 1 will serve this purpose may be employed as an equivalent of the paraffin which it is preferred to embody, and this is to be understood in construing the annexed claims.

The foregoing detailed description has been given for clearness of understandinv only, and no unnecessary limitations should be understood therefrom, but the appended claims yshould be construed. as broadly as'Y permissible, in View of the prior art.

What I regard as new, and desire to secure by Letters Patent,- is:

l. A drycell comprising a zine cup, a core therein comprising carbonaceous material, a wrapper of thin fabric on said core having' upper and lower margins provided with resistant adhesive insulating coatings and formed into tucks pressed against the upper and lower surfaces of the core, said tucks being secured in position by said adhesive coating, the portion of the wrapper enveloping the circumferential surface of the core being unin'lpregnated with the adhesive, and an electrolyte between the wrapped core and the zinc cup.

For' use in a dry cell, a Wrapped core comprisinga depolarizing body and a bibulons wrapper enveloping said body, said wrapper having its lower margin impr-eg ated with an adhesive of insulating character, said margin being pressed in folds against the lower surface of the core and .said folds being secured in place by said 'adhesive and the portion of the wrappcrem vclopingthe cylindrical surface of the core beingl left unimpregnated.

f3. A wrapped core for use in dry cells comprising a body of depolarizing mix and a wrapper enveloping said body comprising a strip of cheese Vcloth having upper and lower margins impregnated with paraffin and pressed in folds against the upper and lower ends of the core, the portion of the wrapper about said cylindrical coro being lunimpregnated and said folds being secure in position by the paraffin.

4. A wrapped core for use in dry cells fik v comprising Va molded cylindrical body of suitable depolarizingvmix, and a thin Wrapper enveloping said core comprising a strip of cheese cloth wrapped on the corevand having overlapping vertical margins, said Wrapper having upper and lower margins impregnated wxh a Waxfli'ke adhesive, said upper and lower margins being folded in tucks pressed against and adhering to the upper and lower surfaces of the core, the portion of the Wrapper enveloping the-circumferential surface ofthe core being unimpregnated with the adhesive.v

5. The method of Wrapping a core for a dry cell which comprises: impregnating the upper and lower margins only of a thir'r,

non-resilient strip of bibulous material with an adhesive, wrapping the strip about the core, and tueking the impre natedmargins against the end surfaces of Le core and securing the tucks in position by said adhesive. 6. The method of applying an envelope to a. core for use ina dryeell which oomprises: impregnating the lupper and lower margins oa strip of cheese cloth, Wrapping the strip about the core with the impregnated margins projecting in an' annular form, and tucking the annular projecting margins against the upper and lowersurfaces of the core and securing the tucks in positionby means of said adhesive.

LEROY G. BERIGA.' 

